Kinetics of concentration of RhD-positive RBCs (mean ± SD) measured in blood following intravenous (IV) or intramuscular (IM) administration of 1500 IU (300 μg) Rhophylac. The percentage of RhD-positive RBCs remaining in the blood at different times was calculated according to the 100% value determined at +23.5 hours after RBC administration by FACS assay.